Remove outdated benchmarks (#63)

Author: juntyr

.gitattributes

@@ -1,7 +1,3 @@
-bench/era5_t2m_2012_12_01_14:00.nc filter=lfs diff=lfs merge=lfs -text
-bench/era5_tp_2024_08_02_10:00.nc filter=lfs diff=lfs merge=lfs -text
-bench/era5_o3_pv_2024_08_02_12:00.nc filter=lfs diff=lfs merge=lfs -text
-
 examples/data/cems-ercnfdr/data.grib filter=lfs diff=lfs merge=lfs -text
 examples/data/era5-lh/data.nc filter=lfs diff=lfs merge=lfs -text
 examples/data/era5-pr/data.nc filter=lfs diff=lfs merge=lfs -text